1. Field of the Invention
The present invention pertains generally to a disposable liner and filter assembly and, more specifically, to a disposable liner and filter assembly for a tissue float water bath used in histological procedures.
2. Description of the Prior Art
Referring to FIG. 1, a conventional tissue float water bath container is shown, and is generally indicated by reference numeral 10. The bath container 10, as shown, has a generally cylindrical shape and a heating element 12 mounted in the side wall 11. The heating element 12 has a control knob 14 for adjusting the temperature and is connected to an electrical power source by way of cord 16. The container 10 is partially filled with bath water 17 and the heating element 12 serves to heat the container 10 so as to heat and maintain the bath water 17 at the desired warm temperature. A plurality of tissue ribbon sections 18 are shown floating on the surface of the bath water 17 in the bath container 10.
The initial procedure for placing a tissue ribbon into the bath water is by lowering one end in first. The remainder of the ribbon is lowered gradually with a slight pull until the ribbon is in the heated bath water. Using a heated tissue separator 19 (shown in dashed lines), the sections 18 can be easily and uniformly separated from each other. Over-heating or under-heating of the bath water 17 must be avoided. Such temperature changes in the bath water can cause a loss of the valuable ribbon sections 18.
It is also important to insert clean, dust free slides into the flotation water bath. With the aid of a camel""s hair brush, the section is oriented so that it is centrally placed on the slide allowing free margins for subsequent coverslipping and labeling.
The drawback to this procedure, as is commonly known and performed in the field of histology, is that fat tissue and other tissue fragments not properly fixed to the ribbon will immediately fragment and scatter very rapidly upon contact with the warm bath water. This often makes it impossible to retrieve a sufficient microscopic paraffin section. When the water is thus contaminated, something must be done because further use of the contaminated bath water will be disruptive to future procedures utilizing the same bath water.
Normally, at this point, the proper procedure is to discard the bath water, because it is contaminated. Additionally, the bath container must be cleaned, the water prepared again to the required temperature and the necessary chemical(s) added. This water replacement procedure is very time consuming. Also, this type of interruption can occur on several occasions each day. Hence, this critical procedural step is often neglected by technicians due to the time involved in the water replacement. Obviously, then, tissue fragments remain in the contaminated bath water. These fragments can be easily transferred onto another patient""s slides without noticing. This is a problem and can be very critical under microscopic examination. Accordingly, there is a need in the industry for a device that eliminates the often neglected step of completely discarding and replenishing the bath water from the container 10 after every contamination, yet allows the technician to easily and safely clean the bath water 17 and container 10 in the shortest time to eliminate contamination.
The patent art discloses various screens and filtering devices for biological fluids. The Ferrara U.S. Pat. No. 4,377,476 discloses in FIG. 4 a tissue filtering bath for histology which includes a removable tray-like strainer with a porous bottom. According to the patent, the strainer may be disposable. The Itani U.S. Pat. No. 5,837,198 discloses in FIGS. 3 and 11 a container used in tissue treatment which includes a cylindrical side wall and nylon mesh bottom. Other prior U.S. patents which disclose tissue treating baths and/or disposable filters include the following:
However, the prior art patents do not disclose a liner and filter assembly used in a histology treatment bath which is either totally disposable or filter disposable, or has a structure which can be conveniently used and inexpensively manufactured.
In order to overcome the above drawbacks in the prior art structures, the present invention is directed toward a disposable liner and filter for conventional histology water baths that is convenient, inexpensive and easy to use. The liner preferably includes a relatively short vertical wall in the shape of a cylinder or square, depending upon the configuration of the conventional histology bath container. The liner is sized to fit neatly inside the bath container wall and includes a generally horizontal rim or flange extending outwardly from the vertical wall. The rim or flange then extends over and rests on the top of the bath container wall to maintain the liner and filter in position in the bath and bath water. Preferably, the liner top rim or flange can have at least one attachment means for securing the removable liner and filter to the top wall of the tissue float water bath container. In one preferred form, the attachment means is an adhesive tab on the underneath side of the top rim or flange.
The filter portion of the present invention comprises a generally horizontal bottom wall adjacent the lower edge of the liner vertical wall. The filter bottom is preferably made of microcloth material and includes a reinforcing outer rim and a plurality of support members extending crosswise across the flat filter bottom for sandwiching the microcloth filter therebetween and providing support for the central portion of the filter.
In one embodiment, the liner and filter is a single disposable unit. The liner, flange and support members are preferably made of thin cardboard treated to withstand warm fluids for a lengthy period of time, such as for example the materials used for hot drinking cups and the like. The filtering paper is standard microcloth such as used for gelatinous grindates and rapid filtering. In operation, the operator merely places the liner and filter in position within the bath, fills and heats the container with the bath water. After use, the liner and filter are removed, carrying with them any loose tissue fragments, paraffin or other contaminants, thus leaving the bath water clean. Another disposable liner and filter can then be inserted into the bath water, and the next histology procedure performed.
In a second embodiment, the liner and filter are two separate pieces. The liner and outwardly extending horizontal rim or flange are one piece and the horizontal bottom filter is a separate second piece. The liner is provided with an inwardly projecting lip around its bottom edge on which the bottom filter rests. Depending upon whether the conventional histology water bath is cylindrical, rectangular or square, the liner and separate disposable filter are correspondingly circular, rectangular or square in shape. After use, the liner and disposable filter are removed, carrying with them any loose tissue fragments, paraffin or other contaminants. The liner is cleaned and the disposable filter replaced. In this embodiment, the liner can be made of any durable hard type of plastic or other rigid material for permanent use in conjunction with replaceable sheet-like filters.
The liner and filter assemblies of the present invention reduce downtime and save the technician considerable time in eliminating the need to dispose of contaminated water, clean the bath container and refill and reheat fresh water. Further, the risk of contamination is eliminated. Thus, safety to the patient and tissues is increased.
It is therefore an object of the present invention to provide a disposable liner and filter for use in conventional it tissue float water baths for filtering the tissue float bath water upon removal.
It is a further object of the present invention to provide a disposable liner and filter in accordance with the preceding object which will avoid the necessity of repeatedly discarding and replenishing the bath water each time it becomes contaminated during a histological procedure.
Another object of the present invention is to provide a liner and filter in accordance with the preceding objects which has a flat microcloth bottom that is supported adjacent the lower edge of the liner.
A further object of the present invention is to provide a liner and filter in accordance with the preceding object in which the bottom filter includes an outer rim extending completely around the microcloth bottom and a plurality of support members extending in a crisscross pattern from the bottom rim and across the microcloth bottom for sandwiching the microcloth bottom therebetween and providing support to the filtering means.
A still further object of the present invention is to provide a liner and filter in accordance with the preceding objects and which is made in a plurality of shapes and sizes depending on the shapes and sizes of the conventional water bath containers in use.
It is yet another object of the present invention to provide in one embodiment an inexpensive liner and filter of one piece construction which can be removed from the water bath and carry with it all water contaminants so that the bath water can be reused.
Still another object of the present invention is to provide in another embodiment an inexpensive liner and filter of two piece construction which can be removed from the water bath and carry with it all water contaminants so that the bath water can be reused and the liner can be reused after cleaning with a new bottom filter.
Still yet a further object of the present invention is to provide a disposable liner and filter which will conform to conventional forms of manufacture and provide a device that will be disposable, economically feasible and relatively trouble free in use.